Telegraphy.



W M. BRUCE, 1a..

TELEGRAPHY.

APPLICATION map APR-27.1915.

Patented; May 7,1918.

mam-

WILLIAM M. BRUCE, JR., Oli SPRINGFIELD, OHIO.

TELEG-BAPI-IY.

Specification of Letters Patent.

Patented May *7, rare.

Application filed April 27, 1916. Serial No. 94,833.

To (ZZZ who-m it may concern:

Be it known that 1, WILLIAM M. BRUCE, .n, a citizen of the UnitedStates, residing at Springfield, in the county of Clark and State ofOhio, have invented certain new and useful Improvements in lielegraphy,of which the following is a specification.

My invention relates to improvements in telegraphy and relates moreparticularly to improvements in that system of telegraphy devised by meand set forth in my prior Patents 1,146,234 dated July 13th, 1915 and 1,1.46,0 i9 dated July 13th, 1915.

In the said patents I have set forth means for sending uniformelectrical impulses of opposite polarity at the beginning and the end ofa character such as an ordinary Morse character in order that thepotential ina high capacity conductor shall not be built up more in onedirection and thus effect the zero and consequently a distortion of thecharacter. In this system and particularly where the capacity of theconductor is depended upon more or less for holding up the receivingdevice after the impulse of current has been cut-ofi, I have found,particularly on short conductors or conductors of comparatively lowcapacity, that the receiving device may drop back before the impulse ofopposite polarity is applied and thus there would develop a tendency toclip the dashes and in making a character such as an American Morse L,the dash might not be long enough to distinguish it from American MorseT, The present invention therefore has to do with circuits and apparatusfor positively holding the receiving device inits forward or markingposition until it is retracted by the wiping out impulse.

Generally speaking this improvement differs from my former patents inthat in those patents all of the current from the current supply was cutoff at a predetermined interval whether it was for a negative orpositive impulse. In the present system I employ an auxiliary currentsupply which remains on the conductor until the main impulse of anopposite polarity is impressed thereon so that there is a slight amountof current of the same polarity as the last impulse which remains on thecable until the next impulse is impressed thereon. This auxiliarycurrent supply may be very light and need not exceed from 2 to 3 percent. of the voltage of the main current supply which produces theimpulses but it has the effect of keeping the receiving relay in itsoperated. position after an impulse is impressed on the conductor until.an impulse of opposite polarity follows; the result being that thereceiving relay will absolutely follow the movement of the sending mynotwithstanding that the current impulses are cut off at a predeterminedtime as in my former patents and without regard to the length orcapacity of the cable.

In the drawings I have shown a diagram of circuits showing my improvedmethod or system. For the most part the circuits and apparatus from thesending end are the same as those shown. in my former Patent l. ld6,04;9in which the key 41; operates a sending relay (5 which sends an impulseof current from a main battery 13 until the cut-01f relay 0 operates,when the current impulse would be cut oil by grounding the opposite sideof the battery. In my present circuit 1 place in the leads from the mainbattery B to the sending relay Z), auxiliary batteries l3 and B and soarrange the connections that when the cut-off relay 0 moves to aposition to cut off the main battery after an impulse of one polarityhas been impressed on the cable, an auxiliary battery remains incircuit.- For instance, as shown in the drawing, a circuit can be tracedfrom ground through the armature of the cut-ofi' relay and the auxiliarybattery B to the contact on the sending relay 6 and thence through itsarmature to the cable or con ductor while the main battery B is cut offfrom the cable, thus there is negative bat lery of very light potentialflowing to the cable or conductor at all times when the main battery iscut off. V'Vhen the key is depressed causing the sending relay to moveto its other position, the circuit can be traced from ground through thecut-0H relay armature through the main battery and from the positivepole thereof and through the auxiliary battery B in series therewithuntil the cut-off relay 0 operates when the positive pole of the mainbattery will be grounded, leaving the positive auxiliary battery stillin circuit so that while the positive impulse is cut oif there is stilla very slightamount of positive current flowing into the cable.

The method of applying impulses to the cable from the battery B by useof the send ing relay 6 of the cut-off relay 0 is so fully described inmy prior patents mentioned as to require no further detail descriptionhere, but briefly stated, depressing the key (I- operates the localrelay a in a battery circuit therewith. The armature of this relaycloses the circuit from ground at the relay 0 and through the armatureof said relay and through the main battery B, wires 1 and :2 to thesending relay 6 and to ground. This operates the relay 29 causing itsarmature to close the circuit from ground at the relay 0 and itsarmature through battery l3 and auxiliary battery B, wire 3 to thearmature of the relay 6 and wire t to cable or conducton'this also sendsa current impulse through cut-0E relay 0 through the wire 5 which causesthe relay 0 to operate and cuts off the supply of current from the mainbattery but permits the current from the auxiliary battery 13 to flowinto the conductor over the circuit heretofore described by reason ofthe ground connection established through the armature of the relay 0and wire 6 to one of the terminals of the auxiliary battery B. When thekey is released the relay (1 returns to its normal position and sends animpulse from the main battery B through} wires 7 and 2 to the sendingrelay Z) whichfii causes it to operate in the opposite direc-} tion andsend an impulse of current of op-! posite polarity from the main batteryBi and auxiliary battery B to armature of; relay 2') by wire 8 and thusto the cable through wire 4. When the cut-ofi' relay 0 i operates theauxiliary battery B will still supply current to the cable by reason ofthe ground connection established through wire 9 from the armature ofthe relay 0 to the terminal of the auxiliary battery B In order that thereceiving relay cl which is of the usual polarized type may be affectedby this current I employ shunts s and 8 around the duplexing condensersat the apex of the conductor and where condensers are used in thecircuits of the receiving relay I employ shunts around them also. Theresult is that this small amount of current flowing to the conductorwill be suiiicient to hold the delicate relay in its last operatedposition until it is positively moved. in the other direction by acurrent impulse from the main battery in the usual Way.

I have found in working on a circuit from ll aterville, Ireland toCanso, Nova Scotia that this arrangement of the auxiliary current supplynot only renders the receiving instrument positive in its operation indots and dashes and causes it to hold the clashes as long as the key isdepressed, but it also has a tendency to render the conductor lesssensitive to duplex disturbances which might vary the operation of thereceiving device and cause a distortion of the character.

Having thus described my invention, I claim 1. In a system such asdescribed, in which impulses of opposite polarity are applied to a cablefor a predetermined interval at the beginning and end of a character, anauxiliary current supply arranged and adapted to be used in conjunctionwith the main supply when the impulse is supplied and to remain incircuit with the conductor after the main supply is cut off and until asucceeding impulse of opposite polarity is applied.

2. In a system, such as described, a main battery and means forsupplying impulses of opposite polarity therefrom for a definite time,auxiliary batteries of opposite polarity one of which is adapted toremain in circuit with the conductor after the main supply is out 01?,in combination with a polarized receiving device which will be held ineither operated position by one of said auxiliary batteries.

f 3. In a system such as described, a main battery and auxiliarybatteries, means for causing said main battery to discharge current ofopposite polarity 1n con unct1on with one of said auxiliary batteriesand for ,'cutting off said main battery and leaving the auxiliarybattery in circuit until an impulse of opposite polarity from the mainbattery is applied.

4. In a system such as described, having a sending apparatus for,sending impulses of current of opposite polarity for a definite time andincreasing these impulses by auxiliary current supply and causing saidauxiliary supply to remain on the conductor after the main supply hasbeen cut off, a receiving device which is moved in one direction by animpulse of one polarity and in the opposite direction by an impulse ofanother polarity, duplexing condensers in the sending end of theconductor, and shunts around said condensers as and for the purposespecified.

In testimony whereof, I have hereunto set my hand this 18th day ofNovember,

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Eatents.

Washington; D. (1.

